Some maritime boundaries have remained indeterminate despite efforts to clarify them. This is explained by an array of factors, some of which involve regional problems.[4]

The delineation of maritime boundaries has strategic, economic and environmental implications.[5]

Terminology

The terms boundary, frontier and border are often used as if they were interchangeable, but they are also terms with precise meanings.[6]

A boundary is a line. The terms "frontier", "borderland" and "border" are zones of indeterminate width. Such areas forms the outermost part of a country. Borders are bounded on one side by a national boundary.[7] There are variations in the specific terminology of maritime boundary agreements which have been concluded since the 1970s. Such differences are less important than what is being delimited.[8]

Limits

The limits of maritime boundaries are expressed in polylines and in polygon layers of sovereignty and control,[10] calculated from the declaration of a baseline. The conditions under which a state may establish such baseline are described in the United Nations Convention on the Law of the Sea (UNCLOS). A baseline of a country can be the low water line, a straight baseline (a line that encloses bays, estuaries, inland waters,...) or a combination of the two.[1]

Zones

The zones of maritime boundaries are expressed in concentric limits surrounding coastal and feature baselines.[1]

History

The concept of maritime boundaries is a relatively new concept.[1] The historical record is a backdrop for evaluating border issues.[12] The evaluation of historic rights are governed by distinct legal regimes in customary international law, including research and analysis based on

The study of treaties on maritime boundaries is important as (a) as a source of general or particular international law; (b) as evidence of existing customary law; and (c) as evidence of the emerging development of custom.[14] The development of "customary law" affects all nations.

The attention accorded this subject has evolved beyond formerly-conventional norms like the three-mile limit.

Treaties

Multilateral treaties and documents describing the baselines of countries can be found on the website of the United Nations.[1]

For example, the Australia-France Marine Delimitation Agreement establishes ocean boundaries between Australia and New Caledonia in the Coral Sea (including the boundary between Australia's Norfolk Island and New Caledonia). It consists of 21 straight-line maritime segments defined by 22 individual coordinate points forming a modified equidistant line between the two territories.[11]

Disputes

Controversies about territorial waters tend to encompass two dimensions: (a) territorial sovereignty, which are a legacy of history; and (b) relevant jurisdictional rights and interests in maritime boundaries, which are mainly due to differing interpretations of the law of the sea.[15] An example of this may be reviewed in the context of the ongoing Kuwait-Iraq maritime dispute over the Khawr Abd Allah waterway.

Many disputes have been resolved through negotiations,[16] but not all.

Unresolved maritime boundaries

The disputed maritime border between North and South Korea in the West Sea:[17]A:Northern Limit Line, created by the United Nations in 1953[18]B: "Inter-Korean MDL in the Yellow Sea", declared by North Korea in 1999[19] The locations of specific islands are reflected in the configuration of each maritime boundary, including

Among the array of unsettled disputes, the maritime borders of the two Koreas in the Yellow Sea represent a visually stark contrast.[17]

A western line of military control between the two Koreas was unilaterally established by the United Nations Command in 1953.[20][21] Although the North asserts a differently configured boundary line, there is no dispute that a few small islands close to the North Korean coastline have remained jurisdiction of the United Nations since 1953.[22]

The map at the right shows the differing maritime boundary lines of the two Koreas. The ambits of these boundaries encompass overlapping jurisdictional claims.[23] The explicit differences in the way the boundary lines are configured is shown in the map at the right.

In a very small area, this represents a unique illustration of differences in mapping and delineation strategies.

On one hand, the boundary line created by the United Nations ("A") reflects the geographic features of the coastal baseline.[18]

On the other hand, while the boundary line declared by North Korea does acknowledge specific non-DPRK island enclaves, its "Military Demarcation Line" in the ocean ("B") is essentially a straight line.[19]